Thermal processor

ABSTRACT

A THERMAL PROCESSOR FOR HEATING WEB MATERIAL IN A WELL-KNOWN MANNER BETWEEN A ROTATING DRUM AND A MATING, NON-ROTATING, SEMI-RIGID RESILIENT SHELL. A PIVOTALLY, CONNECTED SUPPORT MEANS HOLDS THE SHELL IN &#34;FLOATING&#34; RELATIONSHIP WITH THE DRUM. SUCH RELATIONSHIP IS ACHIEVED BY THE USE OF LINKS WHICH PIVOTALLY CONNECT THE SUPPORT MEANS AND SHELL WHICH PERMIT LIMITED MOVEMENT OF ANY PORTION OF THE SHELL IN A GENERALLY RADIAL DIRECTION RELATIVE TO THE DRUM WHILE PREVENTING THE SHELL, AS A WHOLE, FROM ROTATING WITH THE DRUM.

Feb. 9, 1971 F. D, HAUCK THERMAL PROCESSOR 2 Sheets-Sheet 1 Filed March21, 1969 FEEDER/C D. HAUCK INVENTOR.

AGENT Feb. 9, 1971 F. D, HAUCK THERMAL PROCESSOR 2 Sheets-Sheet 2 FiledMarch 21, 1969 FEEDER/C D. HAUCK INVILN'IOR.

AGENT United States Patent 3,561,133 THERMAL PROCESSOR Frederic D.Hauck, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester,N.Y., a corporation of New Jersey Filed Mar. 21, 1969, Ser. No. 809,074

Int. Cl. F26b 1/02 US. Cl. 34-110 8 Claims ABSTRACT OF THE DISCLOSUREFIELD OF THE INVENTION This invention generally pertains to animprovement in a thermal photographic processor utilizing a rotatingdrum and a cooperating, non-rotating, semi-rigid, resilient shell. Moreparticularly, the invention pertains to means for supporting the shellrelative to the drum.

I DESCRIPTION OF THE PRIOR ART Thermal photographic processors of thetype disclosed herein are used to apply heat to Web materials in theform of paper, film or the like. Generally, such processors include amotor-driven, frame-mounted drum that is rotatable about a fixed axis,and a semi-rigid, resilient, non-rotating shell having a structurecomplementary to that of the drum such that the shell is biased intocontact with and wrapped partially around the periphery of the drum. Thelimit of the shells peripheral contact with' the drum is established bythe ends of the shell which are transverse to the direction of the drumsrotation and which leave a portion of the drum uncovered to provideaccess to the facing surfaces of the drum and shell. Typically, amaterial having a relatively high coefficient of friction, e.g.,silicone rubber, is used to form the facing or peripheral surface of thedrum, while a material having a relatively low coefficient of friction,e.g., tetrafluoroethylene (sold under the trademark Teflon), isgenerally used for the facing surface of the shell.

In the processing cycle of this type of apparatus, the Web material tobe processed is inserted into the apparatus between the facing surfacesof a shell and a drum so it can be moved with the drum beneath the shellthat partially surrounds the drum and is resiliently urged thereagainst.During this movement, heat is applied to the web either through theshell or the drum, as well as pressure which results from the coactionof the shell and drum to cause the desired processing action to takeplace. When the web material reaches the trialing transverse edge of theshell, it is removed from the apparatus.

Preferably, predetermined amounts of heat and pressure are applied tothe web material for a predetermined time period to carry out theprocessing cycle. To provide optimal thermal processing with suchapparatus, the web should be held against the heated element (drum orshell) with a fairly constant pressure so as to have uniform contactwith both the drum and shell. A shell used in apparatus of the abovetype is partially wrapped around and biased into contact with therotating drum in an attempt to maintain the desired uniform contactthrough- 3,561,133 Patented Feb. 9, 1971 out the entire area of contact.Consequently, the shell is made somewhat resiliently flexible tomaintain such uniform contact. Further, in order to provide a certainamount of shell resiliency, while preventing rotation of the shell withthe drum, one end of the shell is pivotally connected above a fixed axiswhich maintains that end of the shell in a fixed position relative tothe drum. Spring means, acting between the other transverse end of theshell and the frame of the apparatus, urge the shell into contact withthe drum.

A major problem arises with such prior art apparatus because, when theshells leading end is thus fixed and its trailing end is spring-biased,operation of the apparatus produces frictional forces which tend tocause the shell to wrap tightly around the drum, thereby increasing itspressure thereagainst and introducing fractional forces which willdepend on the relative coefficients of friction of the shell surface anddrum surface. To avoid this tighening effect, the prior art disclosesthat the shells ends can be connected in an opposite manner, i.e., withthe trailing edge of the shell pivotally fixed and the leading edgespring-biased. However, with this arrangement the frictional forces thatare produced tend to cause the shell to move away from the drum, therebyobtaining an effect that is converse to the desired uniform contact.

With the aforementioned arrangements, an excessive pressure tends tocause the shell to bind with the drum and insufficient pressure resultsin wrinkling of the web material and/ or inefficient heating thereof.

Further, with both of the prior art arrangements described above, oneend of the shell is always in a fixed relation to the drum and, hence,it is not possible to compensate for any variations in web thickness. Inaddition, thermal processing apparatus is subject to relatively hightemperatures, as well as temperature variation, so that further problemsare generally created by corresponding thermal expansion and contractioneffects. These effects result in changes in the dimensions of theapparatus components and cause them to assume a modified orientationrelative to each other. This problem is particularly critical withrespect to the fixed, hinged end of the shell, since relatively smallmovements of this hinged end toward or away from the drum result inrelatively large changes in the pressure to which the web is subjectedas it passes therebetween.

Still another problem is prevalent in that a heavy load is placed on thedrive motor when the drum is driven with no web material between thedrum and the shell due to the frictional force generated between thefacing surfaces. However, insertion of web material between the drum andthe shell generally reduces the aforementioned frictional force becauseof the much lower coeflicient of friction which exists between the webmaterial and the shell and drum so that the load on the motor isreduced. Such variations in load frequently result in large enoughchanges in the speed of the motor to have detrimental effects onprocessing cycle time peroids.

SUMMARY OF THE INVENTION A primary object of the invention is to providea thermal processor of the above type wherein a shell mountingarrangement for use in such processor that will minimize theabove-described problems, while still retaining the advantages inherentin such apparatus.

Another object of the invention is to provide a floating shell-mountingarrangement for use in a thermal processor which permits radial movementof all parts of the shell relative to the drum and providing automaticcompensation for variations in web thickness, for variations in theexpansion and contraction of component parts of the Web and shellassembly, and for variation in the load on the drive motor.

These objects and others, which will become apparent on reading thefollowing detailed descriptiomare achieved in accordance with theinvention disclosed herein by supporting the shell so that it is infloating contact with the rotating drum. Such floating contact isachieved by the use of links which pivotally connect the shell to theframe of the apparatus to provide for limited movement of any portion ofthe shell in a generally radial direction relative to the drum whileholding the shell against rotational movement with the drum. These linksare preferably attached to the shell at points intermediate its leadingand trailing transverse ends, thereby dividing the shell intoessentially two zones. Under the effect of friction occurring duringoperation of the apparatus, in one zone, the shell will tend to moretightly wrap around the drum, while in the second zone, the shell tendsto unwrap or loosen. At the same time, the shell is continually urgedtoward and into contact with the drum by resilient means, e.g., springs,acting between the. shell and frame.

DESCRIPTION OF THE DRAWINGS The invention will now be described ingreater detail with reference being made to the accompanying drawingswherein:

FIG. 1 is a fragmentary perspective view of the web heating apparatusshowing a drum and shield arrangement in accordance with the invention;

FIG. 2 is a partial cross-sectional view of the embodiment shown in FIG.1, including a web of material passing between the drum and shell;

FIG. 3 is a fragmentary perspective view of the shield shown in FIG. 1and showing the manner in which a link can be pivotally connected to theshield;

FIG. 4 is a rear view of an alternative embodiment of the invention; and

FIG. 5 is a fragmentary perspective view showing the pivotal arrangementfor mounting the shield shown in FIG. 4.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, theapparatus comprises a drum I mounted on a shaft 3 which is driven by amotor 4 through a suitable coupling designated by the dotted linebetween said shaft and motor. The ends of shaft 3 are journaled in aframe 5 which comprises a pair of end plates 7 (only one of which isshown). The drum 1 rotates about the axis 9 of the shaft 3 and theperipheral surface 11 of drum 1 is coated with a material having arelatively high coefficient of friction, such as silicone rubber. Aresilient, semi-rigid, non-rotatable shell 13 has an interior surface 15that is coated with a material having a relatively low coeflicient offriction, such as tetrafluoroethylene, which is marketed under thetrademark Teflon. The shell 13 is arranged to partially surround thedrum 1 with the surfaces 11 and 15 being in facing and contactingrelationship, as shown in FIG. 2. Access to the drum .1 and the surfaces11 and 15 is provided by extending the transverse ends 17a and 17b ofthe shell 13 beyond the full width of drum 1 in an axial direction. Theexterior surface of the shell 13 can be coated with a material in whichheating elements 19 can be disposed to provide a source of heat for aweb material 21 which is to be processed by the apparatus.

The web material 21 is inserted between the surfaces 11 and 15 adjacentthe leading end 17a of the shell 13. Since the coeflicient of frictionbetween the web material 21 and the drum surface 11 is greater than thatbetween the web material 21 and the shell surface 15, the web material21 adheres to the surface of the drum 1 and moves therewith subsequentlyexiting from the apparatus at the trailing end 17b of the shell 13.

In accordance with the invention, the shell 13 is mounted for floatingcontact relative to the drum 1 in order that the apparatus will operatesmoothly when web material 21 is inserted and moved therebetween. Such amounting means provides more uniform and less extreme pressures andcontact than were previously attainable. This mode of obtaining afloating contact is achieved by pivotally connecting the shell 13 to theframe 5 to prevent rotation of the shell 13 with the drum 1 and at thesame time permitting limited and generally radial movement of the shell13 relative to drum 1 throughout its axial length. The mounting meansutilized for this purpose comprises a pair of links 23 interconnectingthe shell 13 and frame 5. The links 23 are connected to the frame 5 bymeans of a rod 25 which is oriented parallel to the axis 9 of the shaft3 and is attached to the end plates 7 by inserting its opposed ends in apair of directly opposed holes 27 in the end plates. Each of the links23 has a looped end 23a and is pivotally connected to the rQd 25adjacent its opposed ends, so that the links 23 can swing in a generallyvertical plane. The links 23 are attached to the shell 13 by insertingeach of their hooked ends 23b (FIG. 2, 3) into one of the opposed pairof holes 29 in the shell 13 adjacent each of the side edges 30. Suchattachment of the shell '13 limits its twisting, tilting and pivotalmovement relative to the drum 1.

Biasing means are preferably provided to urge the shell 13 toward andinto contact with the drum 1. Such biasing means comprises tensilesprings 31 which are interconnected between rods 33 to which the leadingand trailing ends of shell 13 are secured and adjustable anchors 35located on the end plates 7. The biasing means can also includecompression springs 37 which are arranged between adjustable anchors 39on the end plates 7 and the shell 13. While the springs 37 can belocated at various selected points relative to the shell 13, such pointshould, preferably, be between the leading end 17a and the point ofattachment of the link 23 to the shell .13. Accordingly, the shell 13 isthen biased into contact with the drum 1 at such selected points.

The shell suspension described above provides automatic compensation forthe variable expansion and contraction of parts due to temperaturechanges occurring during the thermal photographic process as well as forthe presence or absence of the web material in the apparatus. Suchautomatic compensation is smoothly achieved in view of theself-adjusting radial movement,

the limited twisting movement, the tilting movement and/ or the pivotalmovement of the shell 13 relative to the drum 1. Moreover, the floatingconnection permits a greater range of web thicknesses to be readilyprocessed than was previously possible.

As noted above, insertion of the web material 21 into the apparatus canresult in a considerable variation in the load on the drive-motor 4. Themagnitude of this variation in load is a function of the position of thepoint of attachment of the links 23 to the shell 13. Therefore, aplurality of the pairs of holes 27 and the pairs of holes 29 is providedso that alternative points of attachment are available, therebyobtaining optimal operation of the apparatus under various operatingconditions. The optimum position of the links 23 for achieving minimumvariation in the load does not necessarily coincide with that positionat which optimum shell pressures can be achieved. A compromise can bereached by selecting, from the various pairs of available holes, thosewhich will yield, in combination, acceptable pressures and range invariation of load.

In a second embodiment of this invention (FIGS. 4 and 5), the mountingmeans comprises a fixed member and a pivotal member. A channel member41, comprising the fixed member, has a projection 42 extending from eachof its opposed ends for insertion in the holes 27 of the end plates 7. Arod 43, comprising the pivotal member, is pivotally mounted within theconfines of the channel member 41 by means of a pin 44, the rod 43 beingmovable about an axis that is generally perpendicular to that of member45. A pair of links 46 are then pivotally mounted adjacent the ends ofrod 43. The complemental structure of this embodiment is similar to thatof the first embodiment except that the shell 4-7 is of a more rigidnature. The second embodiment thereby provides specific means fordividing those forces which are tending to cause rotation of the shell,generally equally between the links. Also, the second embodiment is moreappropriately used with a rigid shell than a semi-rigid shell. Thesemi-rigid shell, as used in the first embodiment of this invention, candivide the rotational forces between the links because of itsflexibility. However, a rigid shell is much less flexible and thereforecannot do so. Thus, auxiliary means, as shown in the second embodiment,are desirable to provide this equalizing action.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected Within the spirit and scopeof the invention.

I claim:

1. In a thermal processor of the type having a drum mounted on a framefor rotation in a predetermined direction for moving a web of materialpositioned between said drum and a complementary shaped, non-rotatable,resilient, semi-rigid shell partially surrounding said drum, said shellbeing heated for subjecting said web material to said heat while beingmoved between said drum and said shell, the improvement comprising:

connecting means between said frame and said shell for maintaining thelatter in floating contact with said drum and web of material;

said connecting means comprising a pair of spaced links pivotallymounted on said frame and engaging said shell for substantiallymaintaining said shell against rotation in the direction of rotation ofsaid drum while permitting generally radial movement of said shell,toward and away from said drum, throughout its peripheral extent.

2. The processor in accordance with claim 1 including resilient meanslocated between said frame and said shell for biasing the latter towardsaid drum.

3. The processor in accordance with claim 1 wherein said frame comprisesa pair of spaced, substantially parallel plates and mounting meansarranged therebetween and spaced from said shell with each end of saidmounting means engaging one of said plates and wherein each of saidlinks is pivotally mounted on said mounting means adjacent one of saidplates.

4. The processor in accordance with claim 3 wherein said mounting meanscomprises a fixed member which is disposed between said plates in spacedand parallel relation to said drum and a pivotal member which ispivotally connected intermediate its ends to said fixed member formovement in the generally vertical axial plane of said fixed member,said links being pivotally mounted in said pivotal member.

5. The processor in accordance with claim 3 wherein said shell has aleading and a trailing end both of which extend transverse to thedirection of rotation of said drum, one end of each said links beingselectively connectable to said shell at any one of a plurality ofpositions about its periphery and intermediate said leading and trailingends, and each end of said mounting means selectively engages one ofsaid plates at any one of a plurality of positions.

-6. The processor in accordance with claim 5 including resilient meansarranged between said frame and the 1eading and trailing ends of saidshell for radially biasing said shell into contact with said drum.

7. The processor in accordance with claim 6 wherein said resilientbiasing means includes spring means arranged between said frame and saidshell and engaging the latter between its leading end and its point ofattachment with said links for radially urging said shell toward saiddrum.

8. The processor in accordance with claim 3 wherein each of said platesis provided with a plurality of serially disposed holes for receiving arespective end of said mounting means, whereby said mounting means canbe positioned selectively relative to said holes and to said shell.

References Cited UNITED STATES PATENTS 1,392,621 10/1921 Bochrnan 341463,311,040 3/1967 Ishikawa 2l9388X 3,469,077 9/1969 Peterson et al219-316X MARTIN P. SCHWADRON, Primary Examiner T. W. STREULE, AssistantExaminer US. Cl. X.R. 219-388

